[PATCH] ld: Clarify --wrap documentation

Hans-Peter Nilsson hp@bitrange.com
Thu Jan 10 20:16:00 GMT 2019


On Thu, 10 Jan 2019, Sebastian Huber wrote:

> ld/
> 	ld.texi (--wrap): Add example to emphasise that only undefined
> 	references are replaced by the linker
> ---
>  ld/ld.texi | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/ld/ld.texi b/ld/ld.texi
> index cc0d220fa0..03c5581a3b 100644
> --- a/ld/ld.texi
> +++ b/ld/ld.texi
> @@ -2392,6 +2392,25 @@ you should not put the definition of @code{__real_malloc} in the same
>  file as @code{__wrap_malloc}; if you do, the assembler may resolve the
>  call before the linker has a chance to wrap it to @code{malloc}.
>
> +Only undefined references are replaced by the linker.  So, module internal
> +references to @var{symbol} are not resolved to @code{__wrap_@var{symbol}}.  In
> +the next example, the call to @code{f} in @code{g} is not resolved to
> +@code{__wrap_f}.

The "is not" is too affirmative: what happens depends on the
target and compiler options.  Perhaps "may or may not be"?

> +
> +@smallexample
> +int
> +f (void)
> +@{
> +  return 123;
> +@}
> +
> +int
> +g (void)
> +@{
> +  return f();
> +@}
> +@end smallexample
> +
>  @kindex --eh-frame-hdr
>  @kindex --no-eh-frame-hdr
>  @item --eh-frame-hdr
> --
> 2.16.4
>

brgds, H-P



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